火电厂专业英语

1、1. Modern electric generating stations1.现代发电厂1.1 how power is generated 1.1 电是如何产生的 Virtually all the electric power in the United States today is generated by one of the methods depicted schematically in fig.1.1. 事实上，今天所有的美国电力都是由图1.1所示意的一种方法所产生的。Approximately 90% of the electric power are generated

2、 by what is called the thermal-mechanical generation concept. In this concept, heat energy is converted into mechanical energy which powers an electric generator. Most of these power plants use the Rankine cycle for conversion of heat energy to mechanical power. 接近90%的电力是通过热机发电的理念而产生的。这个观念认为，热能可以转化为

3、机械能，而机械能又可以通过发电机转化为电能，大部分电厂使用朗克循环的方法将热能转化为电能Fossil-fuel plants represent the most common application of the thermal-mechanical concept. 化石燃料电厂是最典型的热电应用Coal, gas, or a petroleum fraction is mixed with air and injected into a boiler where combustion takes place.煤、天然气、石油与空气混合注入到锅炉中进行燃烧。In most plants,

4、heat from combustion is used to convert water to steam. 在大部分电厂中，燃烧产生的热量将水转化成水蒸气。This steam, in turn, flows through large pipes to a multistage turbine.蒸汽流经大型的管道进入多级汽轮机中。In some plants fired by petroleum or gas, the combustion products flow directly to the turbine. 在一些燃油和燃气火电站中，燃烧产物直接流入汽轮机中As the ste

5、am or hot gas passed through the turbine, energy is extracted from the vapor to run the turbine.当蒸汽或热气流经汽轮机时，蒸汽中的能量也流经汽轮机。The turbine is mechanically connected to the generator, and it drives or rotates the generator, allowing the production of electrical energy. 汽轮机和发电机在结构上相联，它驱动发电机转动，产生电能。1.2 Stea

6、m Power Plants1.2 蒸汽发电厂 The most widely used fossil systems burn coal or a heavy petroleum fraction to supply the thermal energy, and employ a steam turbine to power the electric generator.最广泛应用的矿物质燃烧系统是烧煤或者烧油来提供热能，利用蒸汽轮机来驱动发电机。Fossil-fuel plants represent the most common application of the thermal-

7、mechanical concept. 矿物质燃料电厂体现的是最普通的热机发电的理念Coal, gas, or a petroleum fraction is mixed with air and injected into a boiler where combustion takes place. 煤、燃气、石油夹杂在空气中注入正在燃烧的锅炉内。 In most plants, heat from combustion is used to convert water to steam. 在大部分电厂中，燃烧获得的热量用于将水转化为蒸汽。This steam, in turn, flows

8、 through large pipes to a multistage turbine.蒸汽依次流过大型的管道，进入多级的汽轮机中 In some plants fired by petroleum or gas, the combustion products flow directly to the turbine. 以油气为燃料的电厂其燃烧出的蒸汽直接导向汽轮机As the steam or hot gas passed through the turbine, energy is extracted from the vapor to run the turbine.当蒸汽和热气经过

9、汽轮机时，由蒸汽中所散发出的热量推动汽轮机， The turbine is mechanically connected to the generator, and it drives or rotates the generator, allowing the production of electrical energy. 汽轮机与发电机由机械连接起来，由它驱动或者转动发电机，实现发电。Key:HPT=high pressure turbine LPT=low-pressure turbine IPT=intermediate-pressure turbineFigure 1.2 Heat

10、 cycle for a coal-fired boiler Coal has been, and for at the next decade or so will continue to be, the largest source of fuel for electrical generating stations in the United States. 在将来十年甚至一直往后，煤都是美国发电厂最大的燃料来源As early as 1925, coal generated 57% of this countrys electrical power. 1925年，国家靠煤发电57%，

11、Coal generated an average of 52% of the electrical power during the period from 1925 to 1970. 从1925年到1970年，国家靠煤发电52%，Utilities burn about 65% of all the coal mined in the united states. 使用了占全国煤燃料的65%In 1984 it is projected that coal will generate approximately 47% of the electrical power, and 875 mi

12、llion tons of coal will be consumed.在1984年，计算出靠煤发电47 %，消耗了8.75亿吨的煤。 U.S. policy is to move away from the use of petroleum for electric power generation.美国的政策是取缔使用燃油发电 This de-emphasis on petroleum use for electric power generation will take years to take a substantial effect.取缔燃油发电还需要过一些年才能发挥实效 Powe

13、r generation by petroleum dropped slightly in 1947-1975 as a result of the original oil embargo, but in 1976 the use of petroleum rose to an all-time high of 556 million barrels for the generation of 320 billion kilowatt-hours. 在1947年到1975年，由于原油禁运燃油发电略有下降，但是在1976年燃油发电量达到历史最高水平，燃油5.56亿桶，发电3200亿千瓦时It

14、has been estimated that completion of all the petroleum-fired generating units on order during the 1970s will result in a peak use of 900 million barrels of petroleum for power generation should begin to decline thereafter.据估计，七十年代的燃油发电厂的建成，导致燃烧9亿桶燃油发电的使用高峰，这个数值会在今后下降 As coal and nuclear plants assu

15、me a greater share of the base-loaded generation, oil plants will be increasingly used for peak or intermediate power production. 随着燃煤和核电电厂占发电比例的增大，燃油电站会越来越多地用于发电的中介部分However, it is expected that utilities will continue to use substantial amounts of petroleum well into the next century.但是，有人预测，在下一个世

16、纪，燃油还会被使用相当的一部分。Introduction to Power Plant Systems and Components 火电厂系统和部件的介绍The block diagram of Fig.1.3 show the major segments of a modern coal-fired power plant.图1.3所示的方格的内容就是现代火电厂的主机设备的构成。 After crushing and pulverizing, the coal is fed to the furnace, where it is burned. 煤经过粉碎和研磨之后， 被送到炉腔中进行燃

17、烧。In the flame region, much of the heat generated is transferred to boiler tubes which line the walls. 在火焰区，大部分所产生的热量被转移到沿墙壁布置的锅炉管道上。The steam water mixture formed in the boiler tubes proceeds to a steam drum, where the vapor and liquid are separated. 在锅炉管道里的汽水混合物流入到汽包里，在这里进行水汽分离。The liquid is retur

18、ned to the boiler tubes and the vapor proceeds to a superheater. 液体流回锅炉管道，而水蒸气则流入过热器。There the hot gases leaving the flame region superheat the saturated steam produced in the boiler section. 热气从火焰区出来，对锅炉管道里产生的水蒸气进行过热。The superheated steam produced in the boiler section. The superheated steam procee

19、ds to the turbine, where its thermal energy is converted to mechanical energy. 过热后的水蒸气流过锅炉，又流过汽轮机，在这里热能被转化为机械能。 The steam leaving the high-pressure stage of the turbine is reheated in the furnace prior to being sent to the low-pressure sections of the turbine. 蒸汽在离开汽轮机的高压级后，在进入汽轮机低压级之前，在炉腔中被重新加热。The

20、 steam exiting from the low-pressure turbine proceeds to a condenser. 蒸汽离开汽轮机低压级后，进入一个冷凝器中。The liquid from the condenser is reheated in regenerative feed-water heaters, using steam bled from the turbine, prior to being returned to the furnace. 从冷凝器中流出的液体在流回炉之前，利用从汽轮机中流出的蒸汽，在供水加热器中再次加热，凝汽器的凝结水在返回炉腔之前

21、，在再生式给水加热器中利用汽轮机的抽气进行再热。The feed-water then proceeds to the furnace, where it is brought to near saturation in the economizer. 给水流入到炉腔中，它可以在省煤器中达到接近饱和The gases leaving the economizer preheat the entering air and are then discharged through the stack.气体流过省煤器，使空气提前预热，然后释放出来 Particulates in the gas str

22、eam are removed by electrostatic precipitators prior to discharge. In newer plants, the exit gases are also scrubbed to remove SO2.蒸汽中的微粒在被蒸汽被释放出之前，静电除尘器除去。在新电厂中，所释放的气体还要考虑脱硫。The major factor in establishing the size of the power plant components is the required net power output.所建电厂的规模由净发电量所决定。 How

23、ever, the design is significantly affected by the characteristics of the coal being burned, coal delivery methods, combustion technique selected, and constituents of the coal ash.但是，对电厂的设计要考虑到所燃烧煤的特性，煤的运输方法，所选择的燃烧技术，以及煤灰的处理方法。 The most significant coal characteristics are:煤的重要特性是：Moisture content 水份

24、High heating value 热温度Grindability index 可磨系数Ash content 灰特性Ash fusion temperature 灰熔点的温度Sulfur content 硫份These specific coal characteristics are far more meaningful in the design of the equipment and the station than is the rank of the coal being burned.煤的特性在对设备的设计和电厂的设计方面比煤的等级更加重要 Each specific co

25、al characteristic can affect the design of certain plant equipment and components. 煤的每种特性都会对专门的设备和部件都有影响As an example, consider the effect of the moisture on power plant components. 比如，煤的水分对电厂部件的影响 The general effect is to increase most boiler components sizes and to reduce boiler efficiency.总的影响是会增

26、加锅炉部件的尺寸，而减小锅炉的效率A high moisture content will require a larger air heater. 水分越高，越需要更大的空气加热器。This, in turn, requires an increase in the temperature of the inlet air to the pulverizers（粉碎机） since a greater volume of air is required to dry the coal in the pulverizer. 受此影响，需要增加进入粉碎机的空气的温度，因为需要更大体积的空气来干燥

27、在粉碎机中的煤。This increases the initial primary air fan size and reduces the forced draft fan sizes. 这会增加一次风机的尺寸而减小从动风扇的尺寸。The burning of coal with a high moisture content results in a higher flue gas dew point, and raises the stack temperature needed to prevent corrosion. 燃煤含有高水分，会导致高流量的气雾，而且会提高防腐蚀的温度。T

28、he net result of a high-moisture-content coal is to reduce the overall power plant efficiency.高水分煤会减少整个电厂的效率，The high heating value of the coal is another property that significantly affects plant design. 煤的高位发热值是影响电站设计的另外一个重要的特性The high heating value(HHV) establishes the rate at which coal is fed i

29、nto the furnace(firing rate). 高位发热值确定煤被送入炉腔的频率Since the HHV can vary from 19,000 kJ/kg to well over 28,500kJ/kg(12000 Btu/lb) and since the firing rate for a given furnace or boiler out put is inversely proportional to the HHV, it is easy to see that mass firing rates can vary by over 50%. 由于HHV的值会从

30、19000 kJ/kg变化到28,500kJ/kg，而且由于炉腔忽而锅炉的燃烧频率与HHV成反比，所以，燃烧频率很容易改变50%。Thus the HHV will affect the design of the boiler combustion zone, burners, pulverizers, coal feeders, silo storage requirements, coal-handling equipment, and the size of the active and inactive coal storage.因此，HHV会影响到锅炉的燃烧区域，燃烧器，磨煤机、送

31、煤机、筒仓储备需求、输煤设备的设计，以及煤储存的动态与静态。Air fan 风机Air heater 空气预热器Ash fusion temperature 灰熔点温度Ash hopper 灰斗 Boiler 锅炉Burner 燃烧器Coal ash 煤灰Coal feeder 给煤机Coal plant 燃煤电厂Coal-fired power plant 燃煤电厂Coal-handing equipment 输煤设备Condensate pump 凝结水泵Combustion 燃烧Combustion technique 燃烧技术Condensate 燃烧区Condenser 凝汽器Con

32、tent 成分Convert 转换Cooling tower 冷却水塔Crush 破碎Cycle 循环Deaerate 除去空气Dew 露Dew point 露点Draft 通风Drum 锅筒，汽包Economizer 省煤器Efficiency 效率Electric generator 发电机Electrostatic 静电的Electrostatic precipitator 静电除尘器Embargo 禁止进出口，禁运Fan 风机Feed pump 给水泵Feed-water 给水Firing rate 燃烧率Flame 火焰Flue 烟道Flue gas 烟道气Forced-draft

33、fan 送风机Fossil 化石的Fossil-fuel 矿物燃料Furnace 炉腔Fusion 熔化Generator 发电机Grindability 可磨性Grindability index 可磨系数Heater 加热器HHV(High heating value ) 高位发热气Hopper 漏斗Index 系数Kilowatt 千瓦Kilowatt-hour 千瓦时Mechanical energy 机械能Mixture 混合物Moisture 湿度Moisture content 水分Multistage 多级的Nuclear 原子核Nuclear plant 核电站Precipi

34、tator 除尘器Preheat 预热Pressure 压力Primary air fan 一次风机Property 性能Pulverize 磨碎Pulverizer 磨煤机Pump 泵Rankine cycle 朗肯循环Raw 自然的Raw water 原水Reactor 反应堆Regenerative 回热式，再生式Regenerative feed-water heater 回热式给水加热器Reheat 再热Reheater 再热器Reservoir 储水池Reservoir water 库容水Saturate 使饱和Saturate steam 饱和蒸汽Saturation 饱和状态S

35、crub 清洗Separate 分离Silo 储仓Slag 煤渣Stack 烟囱Steam 水蒸气Steam drum 汽包Steam generator 蒸汽发生器Steam turbine 汽轮机Steam-water mixture 汽水混合物Sulfur 硫磺Sulfur content 硫分Superheat 过热Superheated steam 过热蒸汽Superheater 过热器Tower 塔Turbine 叶轮机Vapor 气Virtually 几乎2.Fuel handling and preparation for burning 2.煤的输送和预燃烧2.1 Coal

36、Handing Systems2.1 输煤系统The coal-handing systems at a large modern power plant unload the coal, handle it in the yard, and prepare the coal for burning in the furnace. 大型电厂中的输煤系统卸煤，输煤到煤场，然后准备送入炉腔中进行燃烧。Figure 2.1 is a block diagram which shows the major steps in the coal handling operation at a power

37、plant.图2.1所示意的是在发电厂中输煤操作的主要步骤。Since most coal plants burn pulverized coal, this section focuses on the preparation of pulverized coal. 由于大部分电厂燃烧的是煤粉，这部分将集中用于煤粉的准备。Rail shipment of coal accounts for nearly three-fourths of the coal delivered to U.S. power plants.铁路运输占到了全美电厂输煤总量的四分之三。 Shipments of 10,

38、000 tons or more are quickly unloaded by rapid-discharge bottom railroad cars. A 100-ton load of coal can be discharged from a hopper car in 20 seconds. 运量为1万吨以上的煤能够被迅速卸下，100吨的煤能够在20秒内被卸下。 Some western surface-mined coal and some eastern coal from Pennsylvania, West Virginia, and Ohio is shipped by

39、barge.西部产的煤和东部的宾夕法尼亚，西弗吉尼亚，和俄亥俄所产的煤通过货轮运输。 Barge shipment of coal accounts for approximately 10% of the coat used by U.S utilities. 轮运费用接近占美国用电费用的10%The barges used to ship coal are generally not self-unloading, except for a few barges on the Great Lakes. 用来运煤的货轮逐渐不能够自我卸煤，除了在五大湖上的少数运煤船。The power pla

40、nt must therefore have its own equipment for unloading barge coal. 电厂就应当拥有自己的卸煤装置A typical unloader consists of a tower housing a trolly boom with a clamshell bucket. 一个标准的卸船机包括装有活动小车和大抓斗的高塔。The bucket swings over the barge to load and dumps the coal in hoppers on shore. 抓斗在货轮上来回走动，抓取煤料，在岸上卸下 The re

41、mainder of the coal used by utilities is shipped by either truck or overland conveyer. 剩下的煤由卡车或者陆上传输工具进行运输Overland conveyers are used where power plants are located near large mines. 当电厂和大型煤矿位置较近时，采用陆地传输工具。 Coal stored at a power plant may be placed in either active storage or reserve storage. 电厂的储备

42、煤可以放在活动的煤仓或者是固定的煤仓The active storage supplies the normal power operation while the reserve storage pile is kept for emergencies and delays in regular shipment.活动煤储备用于提供正常情况下的发电，而固定煤储备主要应对一般的输煤过程中的紧急事件和延迟现象。 Current utility practice is to keep large inactive reserves, up to 500,000 tons, to ensure a

43、reliable fuel supply for 60 to 90 days of plant operation.现在的固定储煤可以存储50万吨煤，保证电厂能够供应60到90天的电。 Since reserve storage piles are usually outdoors, frozen coal is a problem often faced by power plants in the north during the winter months. 由于固定储煤是在室外堆放，因此对北方来说，冬天的冻煤现象是一个要处理的问题。Surface moisture on the coa

44、l causes the coal particles to freeze together. 煤表面的水气导致煤粉冻结The difficulties caused depend on the coal particle size. 由煤粒的大小决定问题的难度。Large chunks of coal have weaker ice bonds than small fine particles because the surface-to-volume ratio is much lower.大块的煤比小块煤粉更容易冻结，因为接触表面的比率更小。 Severe winter weather

45、 conditions can cause entire train loads or reserve stacks of coal to freeze together solid. 有几种天气因素会导致由铁路运输和固定储备的煤会冻结成块There are three methods of dealing with frozen coal: heat, mechanical devices, and freeze-control agents(FCAs). The heating operation is performed in an enclosed thawing shed that

46、is heated by steam, electric, or gas heaters. 有三种方法处理冻煤的问题：热，机械装置，解冻机构。加热操作是在一个封闭的融化棚中进行，该棚由水蒸汽，电和气进行加热。This method is becoming increasing expensive. 这种方法的成本绝来越高Alternatively, mechanical devices can be used to shake, crush, or vibrate in order to break up the coal-ice mass.两者相比，机械装置可以摇、压、震碎煤冰块。 Free

47、ze-control agents act as antifreeze to weaken the crystalline structure of the ice bond. 解冻装置能够弱化冰的晶状结构，The most widely use FCA is ethylene glycol.最常用的解冻装置试剂就是乙烯基乙二醇。 It is applied at a few pints per to of coal when the coal is loaded into the car or silo. 当煤被运到车或仓库时，它提供少量的品脱到煤中。 Ethylene glycol has

48、 proved highly successful as freeze-control agent. 乙烯乙二醇作为解冻剂获得很高的成功率。Coal in active storage is generally kept under cover to protect it from moisture and freezing. 而处于传动状态的煤料则被覆盖起来防止水分和冰冻，Large concrete bunkers immediately adjacent to the boiler plant are usually used. In some cases, both the activ

49、e and inactive storage is under cover. 在锅炉室的旁边会有大的煤仓。在一些情况下，运动状态的煤和静止储藏的煤都是被覆盖的。This is particularly true for western coal, much of which is subbituminous, as it tends to produce large quantities of small particles, known as fines. 对于西部的煤更是如此，由于大部分西部煤是亚烟煤，所以它可能产出大量的小颗粒状物。With these coals, dust and m

50、oisture can become serious problems, making closed storage attractive. 使用这些煤，粉尘和水分将是严重的问题，使得封闭储藏非常必要。Large concrete silos are often used for this purpose. The silos are normally kept under a slight negative pressure to minimize dust problems. 建造大煤仓就是出于这个目的。煤仓经常处于微量的负压状态。就是为了使得粉尘问题最小化。Handing Equipme

51、nt 输送设备Very large quantities of coal are handled daily at modern stations.在现代电厂中每天都有大量的煤需要输送 A 600-Mwe unit, at full power operation, handles and burns approximately 300 tons of coal per hour, or 7200 ton of coal per day. 一个600MW的机组，在全额工作状态下， 要每小时输送和燃烧300吨煤，或者是每天7200吨。Some of the coal delivery and r

52、eceiving systems must be designed to handle up to 4000 tons of coal per hour . 一些煤料输送和接收系统，必须要设计成能够输送4000吨煤每小时。One of the major tasks is building the active and reserve “ stacks ” of coal. 一个重要的任务就是要建活动式和固定式的煤堆。Although there are a number of techniques and a wide variety of equipment that can be use

53、d to stack and reclaim coal, stacking conveyers are widely used. 尽管有大量的技术和各种设备用于堆取煤料，但是堆取料机很是应用很广泛。A particularly useful device is the bucket wheel stacker/reclaimer, which is designed to perform both the stacking and reclaiming operation.一个非常有用的装置就是滚轮式堆取料机，它被设计用来即可以堆料，又可以取料。 Such a device would typ

54、ically be used to build long triangular piles by taking coal from a conveyer running parallel to the pile. 这种装置被经常用于从输煤机上卸煤，堆出长三角形的煤堆，这要求输煤机的走向与煤堆平行。When the pile of coal reaches a maximum height, the stacker moves a few feet and continues to build another pile. 当煤堆达到最大高度时，取料机移动一小段距离，继续堆栈另一堆煤。Reclaiming is done by reversing the direction of the wheel and conveyer. 取煤通过改变车轮和传送机的方向来实现。 Other types of in-plant handling systems are lowering wells, teles